HK1246983B - Coupled multi-bands antennas in wearable wireless devices - Google Patents

Description

Coupled multi-band antennas in wearable wireless devices

Cross-application of related applications

This application claims priority to U.S. non-provisional patent application No. 14/811,621, filed on July 28, 2015, entitled “Coupled Multi-bands Antennas in Wearable Wireless Devices,” which is incorporated herein by reference.

Technical Field

The present invention generally relates to systems and methods for wearable wireless communication devices and, in particular embodiments, to systems and methods for providing coupled multi-band antennas with improved performance in wearable wireless communication devices.

Background Art

The industrial design of modern wireless devices is moving towards low-profile devices. These modern wireless devices include cellular phones, tablets, or wearable electronic devices such as watches, glasses, and virtual reality headsets. Wireless devices require multiple multi-band radio frequency (RF) antennas to operate on or near the user. Typical antennas include cellular main antennas, diversity antennas, wireless networking (e.g., WiFi, 802.11, or Bluetooth) antennas, near-field antennas (e.g., near-field communication or wireless charging), and global positioning (e.g., GPS, GNSS, BeiDou) antennas. Multiple multi-band antennas need to be jointly designed to cooperate with each other and with other electromagnetic components such as speakers, LCD displays, batteries, sensors, etc. However, antennas that are close to each other result in low isolation, reduced efficiency, and increased channel interference.

Summary of the Invention

According to one embodiment of the present invention, a wearable wireless device includes: a circuit board; a housing that accommodates the circuit board, the housing having a front and a back, and when worn, the back is arranged to be closer to the user than the front; a first antenna element electrically connected to the circuit board and located on the front of the housing; and a second antenna element electrically connected to the circuit board and located on the front of the housing, wherein the first end of the first antenna element and the first end of the second antenna element are separated by a first distance, and the second end of the first antenna element and the second end of the second antenna element are separated by a second distance.

According to one embodiment of the present invention, a wearable wireless device includes: a first antenna, including a first antenna element and a shared ground plate; a second antenna, including the second antenna element and the shared ground plate; and a housing that accommodates the first and second antenna elements on the front and back sides, with the front side facing away from a user and the back side opposite to the front side, and facing the user, wherein the first end of the first antenna element and the first end of the second antenna element are separated by a first distance, and the second end of the first antenna element and the second end of the second antenna element are separated by a second distance.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

FIG1 illustrates a perspective view of a wearable wireless device according to one embodiment;

FIG2 illustrates a perspective view of a wearable wireless device without housing material according to an embodiment;

FIG3 illustrates a perspective view of a housing of a wearable wireless device according to an embodiment;

FIG4 illustrates another perspective view of a housing of a wearable wireless device according to an embodiment;

FIG5 illustrates another perspective view of a housing of a wearable wireless device according to an embodiment;

FIG6 illustrates yet another perspective view of a housing of a wearable wireless device according to an embodiment;

DETAILED DESCRIPTION

The following describes in detail the making and using of the presently preferred embodiments. However, it should be understood that the present invention provides many applicable inventive concepts that can be embodied in a variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to implement and use the present invention and do not limit the scope of the invention. Furthermore, the described methods and apparatus may be applied to, but are not specifically limited to, antenna placement and design for wireless communication systems.

Modern communication devices are capable of communicating simultaneously on multiple different channels in different frequency bands, increasing data throughput and enabling the provision of multiple simultaneous wireless communication services within a single device. Many wireless communication devices are designed as multi-band devices, capable of communicating on different cellular frequency bands, such as the 700 MHz to 960 MHz band and the 1700 MHz to 2700 MHz band. Wireless devices also often include other features, such as WiFi connectivity on frequency bands such as 2400 MHz, 3600 MHz, and 5000 MHz, GPS on frequencies of 1227 MHz and 1575 MHz, and Bluetooth on frequencies of 2400 MHz to 2485 MHz. Multi-band antennas enable communication on different frequencies or frequency bands. For example, in some devices, cellular service is provided by an antenna or set of antennas configured to communicate on two or more different cellular frequency bands, while auxiliary services are provided by a WiFi/GPS/Bluetooth antenna or set of antennas configured to communicate on the WiFi, GPS, and Bluetooth frequency bands.

However, in some instances, cellular frequency bands and WiFi, GPS, or Bluetooth frequency bands can overlap, causing interference when the cellular and GPS/WiFi/Bluetooth antennas are in close proximity. Furthermore, in smaller devices such as wearable electronic devices (e.g., watches, glasses, and virtual reality headsets), handheld cellular phones, or tablets, antennas operating in similar frequency bands are being packed into increasingly smaller spaces. For example, cellular antennas optimized for the 824MHz to 960MHz and 1700MHz to 2700MHz ranges require significant capacity to operate effectively. These frequencies are close to or overlap with GPS, WiFi, or Bluetooth signals. The overlapping frequency bands, combined with the proximity of cellular and GPS/WiFi/Bluetooth antennas, introduce interference into the antennas. For example, a transmission on a cellular antenna operating in the 1700MHz band can interfere with a GPS signal operating in the 1575MHz band. Interference with these signals is particularly problematic because GPS signals are transmitted from satellites, resulting in weak signals and easily overloaded signal power.

The systems and methods described herein provide for coupled multi-band antennas positioned in close proximity. For example, the systems and methods provide a multi-band cellular wireless antenna and a GPS/WiFi/Bluetooth antenna extending around the top surface of a wearable wireless device. In some embodiments, the multi-band antenna is positioned around the display, along the distal end of the wearable wireless device, and away from the body or skin tissue. This arrangement minimizes adhesion to the skin and body and increases the radiating aperture. Ensuring an appropriate coupling distance between the GPS/WiFi/Bluetooth antenna and the multi-band cellular antenna reduces interference between the antennas.

To reduce the antenna coverage area and the overall size of the wearable wireless device, multiple antennas are placed at the end of the wearable wireless device away from the user. This arrangement enhances wireless connectivity because the antennas are located at the periphery of the wearable wireless device away from the user's body or skin. The antennas can be positioned further away from the body or skin, as the skin may block or attenuate RF signals. In some embodiments, connectivity can also be enhanced by coupling multiple antennas. In other embodiments, a small coverage area can be achieved by providing a shared ground plane (e.g., a circuit board).

An advantage of some embodiments is that the feed points to the two antenna elements are located close to each other on the circuit board. The feed points can be arranged in an area of the circuit board that is free of other components or wires. In other words, the feed points are located in an area of the circuit board where there is little or minimal interference, power outages, or distortion from other electronic components. Using these feed locations in an allocated area of the circuit board surface enhances antenna performance for wearable wireless devices. Additionally, routing portions of the GPS/WiFi/Bluetooth antenna on different sides of the wireless device improves the antenna efficiency of each antenna and enhances their isolation from each other when sharing the same or overlapping frequency bands.

FIG1 illustrates a wearable wireless device 100 that can be worn by a user. Wearable wireless device 100, such as a wearable watch, includes a housing 110, a display 120, and antenna elements 150 and 160. Antenna elements 150 and 160 are located on different sides of a front face 114 of housing 110, away from the user's body and skin. In other words, when worn, back face 115 is positioned closer to the user than front face 114. Front face 114 of housing 110 is opposite back face 115 of housing 110. Front face 114 is connected to back face 115 via side face 116. Display 120 may be located on front face 114, with back face 115 largely covered by a cover (not shown) that is opened to allow battery replacement.

Wearable device 100 may include a first antenna (including antenna element 150) and a second antenna (including antenna element 160). The antennas may be multimode antennas for transmitting, transmitting, and receiving signals across multiple frequency bands. In some embodiments, the first and second antennas may be switching antennas or smart antennas, depending on frequency matching performance. The circuit board's circuitry is configured to monitor incoming or received radio signals from the active antennas.

The first antenna can be used to provide communication capabilities for cellular wireless communication services. The first antenna is capable of communicating in cellular frequency bands such as the 700 MHz to 960 MHz band, the 1700 MHz, 1900 MHz, 2100 MHz, 2500 MHz, and 2700 MHz bands. The second antenna can be used to provide communication capabilities for communication services such as Bluetooth, GPS, and WiFi. In some embodiments, the second antenna is a dual-mode antenna, capable of transmitting, transmitting, or receiving on multiple frequency bands for multiple communication services. For example, the second antenna can be a GPS/WiFi/Bluetooth antenna that receives GPS positioning signals on a GPS frequency, a group of frequencies, or a frequency band. This GPS/WiFi/Bluetooth antenna can also be used to transmit and receive WiFi signals on WiFi frequency bands such as 2400 MHz, 3600 MHz, and 5000 MHz. Furthermore, the GPS/WiFi/Bluetooth antenna can also be used to transmit and receive Bluetooth signals on frequency bands such as 2400 MHz to 2485 MHz.

Antenna elements 150 and 160 can be routed around display 120 and placed along a side or edge of the upper surface of front face 114. Antenna elements 150 and 160 can be arranged conformally with an end, outer/inner surface, or outer/inner surface of housing 110. First antenna element 150 can extend along the upper edge of housing 110, curving around a first corner and a second corner. First antenna element 150 can cover a portion of the upper surface and a portion of a side surface. Second antenna element 160 can extend along the other upper edge of housing 110, curving around a third corner. It can also cover a portion of the upper surface and a portion of a side surface. This arrangement allows GPS/WiFi/Bluetooth antenna element 160 to be placed two distances 111 and 112 away from multi-band cellular antenna element 150. Distances 111 and 112 can be different. For example, distance 112 (discussed below in FIG. 2 ) close to the feed point location of the circuit board can be shorter than distance 111 further away from the feed point location. The arrangement of the distances 111 , 112 , the antenna element and the housing 110 greatly improves antenna coupling and provides adequate isolation.

The antenna elements 150, 160 may comprise a conductive material, such as a metal. The metal may be copper, aluminum, or an alloy of these materials. The antenna elements 150, 160 may comprise a strip of conductive material, such as a metal strip. The antenna elements 150, 160 are generally not exposed to the air outside the housing 110 but are embedded therein. In other words, the antenna elements 150, 160 may be covered by the housing material or the covering material and therefore not visible to the user. One advantage of arranging the antenna elements 150, 160 in this manner is that they are routed away from the user's body/skin and the grounded metal structures (e.g., circuit boards) of the wearable wireless device. This minimizes electromagnetic absorption from the skin/tissue and increases the radiation aperture.

Antenna elements 150 and 160 may comprise different lengths. For example, first antenna element 150 may be a multi-band cellular antenna element, and second antenna element 160 may be a multi-band wireless antenna element for wireless services other than cellular services. Multi-band antenna 160 may be a combination of a GPS antenna element, a WiFi antenna element, and a Bluetooth antenna element. Multi-band antenna 160 may include more or fewer services than these three wireless services. Antenna elements 150 and 160 may be shaped like or approximately an L, or like or approximately a U. Both antenna elements may be curved around one or more corners. For example, multi-band wireless antenna 160 may be curved around one corner, and multi-band cellular antenna 150 may be curved around two corners. Alternatively, antenna elements 150 and 160 may each be curved around one corner. In some embodiments, the antenna elements have the same shape and thickness but different lengths.

Antenna elements 150 and 160 can each be a component of a dipole. The other component can be a ground plane (e.g., circuit board 130 shown in FIG2 ). For example, the first antenna element 150 and the ground plane (e.g., circuit board 130) can form a first dipole, while the second antenna element 160 and the ground plane (e.g., circuit board 130) can form a second dipole. The ground plane is a shared ground plane. The dipole can be a half-wave dipole. Alternatively, the antenna element and the ground plane can form a monopole.

The length of first antenna element 150 is approximately 55 mm to 90 mm, or 70 mm to 90 mm. Optionally, the length of first antenna element 150 is approximately 84 mm. The length of second antenna element 160 is approximately 40 mm to 65 mm, or 50 mm to 65 mm. Optionally, the length of second antenna element 160 is approximately 61 mm. The width of first antenna element 150 is approximately 3 mm to 6 mm, or less than 10 mm, or less than 5 mm. The width of second antenna element 160 is approximately 3 mm to 6 mm, or less than 10 mm, or less than 5 mm. In various embodiments, the widths of first antenna element 150 and second antenna element 160 may be the same. The thickness of antenna elements 150 and 160 may be greater than 3 mm.

Housing 110 may include distances, regions, or spacings 111 and 112 between antenna elements 150 and 160. Regions 111 and 112 are designed to provide radiation and electrical isolation between the two antenna elements 150 and 160. Regions 111 and 112 may be used to reduce or minimize electromagnetic coupling between the two antenna elements 150 and 160. Housing 110 may be made of a plastic material, such as a thermoplastic material (e.g., polycarbonate/acrylonitrile butadiene styrene (PC/ABS)), a glass material, or a rubber material. The material may be a dielectric material. The material of housing 110 may have a relative dielectric constant of approximately 2 or 2.5. Alternatively, the material may have a higher relative dielectric constant, such as up to 4.4. In other embodiments, housing 110 has a relative dielectric constant of approximately 2.5 to 3.5 or 4.4. The higher the relative dielectric constant of the covering material, the shorter the antenna elements 150 and 160 can be. However, the higher the relative dielectric constant of the covering material, the lower the antenna efficiency. Antenna efficiency is particularly good when the length of a cellular antenna is approximately 84 mm, the length of a wireless antenna (such as Bluetooth) is approximately 61 mm, and the relative dielectric constant of the material of the housing 110 is approximately 2.5.

Antenna elements 150 and 160 may be embedded in the housing material of housing 110. Alternatively, antenna elements 150 and 160 may be located on the surface of housing 110 and covered with a covering material. The covering material may have the same or similar electrical properties as the housing material. In one embodiment, the housing material of housing 110 may have a different relative dielectric constant than the coating material.

2 shows the wearable wireless device 100 without the housing 110 (but with the antenna elements 150 and 160), so that the interior of the wearable wireless device 100 can be seen. In addition to the components described above, the wearable wireless device 100 may also include a circuit board 130 and a battery 140 below the circuit board 130.

Circuit board 130 can be a printed circuit board (PCB), such as an 8-layer, 10-layer, or 12- to 14-layer board having 8, 10, 12, 13, or 14 layers of conductive material, or components separated and electrically isolated by dielectric or insulating layers such as fiberglass, polymers, etc. The conductive layers are electrically connected through vias and can collectively constitute a ground plane. Components such as display 120, touch screen, input buttons, transmitter, processor, memory, battery 140, charging circuitry, and system-on-chip (SoC) structures can be mounted on or connected to circuit board 130, or electrically connected to conductive layers within circuit board 130.

First antenna element 150 is connected to circuit board 130 at a first feed point 134 located on one side 135 of circuit board 130. Second antenna element 160 is connected to circuit board 130 at a second feed point 136 located on the same side 135 of circuit board 130. Alternatively, first feed point 134 and second feed point 136 may be located on adjacent sides 135, 137 of circuit board 130 near a corner. Feed points 134, 136 may be connected to antenna elements 150, 160 via conductive connections 151, 161. Feed points 134, 136 may be located near one corner of circuit board 130 and away from other corners of circuit board 130.

Feed points 134, 136 may be located in an area of circuit board 130 where there are no wires, components, or parts in that area (except for wires connecting feed points 134, 136 to other wires, components, or parts of circuit board 130). The circuit board may include only insulating material in that area, without conductive material. Feed points 134, 136 may be spaced approximately 10 mm to 50 mm apart, or 20 mm to 40 mm apart.

In some embodiments, the distance _d1 between the ends of two antenna elements 150, 160 in region 111 is longer than the distance _d2 between the other ends of these antenna elements 150, 160 in region 112. Therefore, the longest open ends of the antenna radiating arms (antenna elements 150, 160) are routed in opposite directions from the antenna feeds 134, 136. In some embodiments, the distances _d1 and _d2 may be between 10 mm and 50 mm.

2, another advantage is that the antenna elements 150, 160 are not only away from the body tissue/skin, but also away from the ground plane 130 (grounded metal structure). This reduces electromagnetic attraction from the skin, interference from the ground plane and increases the radiation aperture.

FIG3 shows a perspective view of housing 110 according to some embodiments. Antenna elements 150, 160 are located on front surface 114 of housing 110. Front surface 114 of housing 110 includes top surface 118 and side surfaces 116. An opening 125 in top surface 118 of housing 110 is used to support display 120. Antenna elements 150, 160 are located only on top surface 118 and not on side surfaces 116. Antenna elements 150, 160 are generally not visible from the outside because they are embedded in or near the outer surface of housing 110 or are covered by a thin layer of cover coating, which protects antenna elements 150, 160 from scratches or other damage.

FIG4 shows another perspective view of housing 110 according to another embodiment; antenna elements 150 and 160 are located on front surface 114 of housing 110. Similar to FIG3 , front surface 114 includes a top surface 118 and side surfaces 116. Top surface 118 includes an opening 125 for supporting display 120. Antenna elements 150 and 160 are curved around edges and corners 161, 162, and 164, so that they are located on portions of top surface 118 and side surfaces 116. In some embodiments, edges and corners 161 to 164 are rounded and non-angular. Antenna elements 150 and 160 are embedded within and positioned adjacent to the outer surface of housing 110 or covered by a (thin) coating.

FIG5 shows another perspective view of housing 110 according to some other embodiments; antenna elements 150 and 160 are positioned on front surface 114 of housing 110. Similar to FIG3 , front surface 114 includes a top surface 118 and side surfaces 116. However, side surfaces 116 are connected to top surface 118 via inclined, sloped, or angled connecting surfaces 171 through 174. Top surface 118 includes an opening 125 for supporting display 120. Antenna elements 150 and 160 are curved around edges and corners 161, 162, and 164 so that they are positioned within the area of inclined surfaces 171 through 174. Antenna elements 150 and 160 may be positioned over a portion of top surface 118 and a portion of side surface 116. In some embodiments, the edges between top surface 118 and the inclined surfaces, the edges between the inclined surfaces and side surfaces 116, and corners 161 through 164 are rounded rather than angular. The antenna elements 150 , 160 may be embedded in and placed close to the outer surface of the housing 110 or covered by a (thin) coating layer.

FIG6 shows another perspective view of housing 110 according to another embodiment. Antenna elements 150 and 160 are located on front surface 114 of housing 110. Similar to FIG3 , front surface 114 includes an upper surface 118 and semi-bullonized or fully bullnose corners 113, 115, 117, and 119 connecting to the rear surface. Upper surface 118 includes an opening 125 for supporting display screen 120. Antenna elements 150 and 160 are curved around corners 161, 162, and 164, so that they are positioned partially over upper surface 118 and partially over bullnose corners 113, 115, 117, and 119, or only partially over bullnose corners 113, 115, 117, and 119. Corners 161 to 164 are rounded without sharp corners. Antenna elements 150 and 160 are embedded within the outer surface of housing 110 and are positioned close to the outer surface of housing 110 or covered by a (thin) coating.

In some embodiments, the dimensions of the wearable wireless device may be 43 mm x 43 mm x 11 mm.

Embodiments of the present invention include a method for a user to wear a wearable wireless device. The method may include the wireless device according to the previous embodiment. The wearable wireless device can be worn not only on the wrist, but also on any part of the human body (e.g., a necklace, glasses, etc.).

Although the present invention has been described with reference to illustrative embodiments, this description is not intended to limit the invention. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will become apparent to those skilled in the art upon reference to this description. Accordingly, the appended claims are intended to cover any such modifications or embodiments.

Claims (19)

1. A wearable wireless device, characterized in that it comprises at least: Circuit board; A housing that houses the circuit board, the housing having a front and a back, wherein when worn, the back is positioned closer to the user than the front; A first antenna element, electrically connected to the circuit board and located on the front side of the housing; and The second antenna element is electrically connected to the circuit board and is located on the front side of the housing. Wherein, the first end of the first antenna vibrator and the first end of the second antenna vibrator are spaced apart by a first distance, and the second end of the first antenna vibrator and the second end of the second antenna vibrator are spaced apart by a second distance; the front side includes an upper surface, the back side includes a lower surface, the inclined surface connects the side to the upper surface, the first and second antenna vibrators are located on the inclined surface and are located around the display, along the end of the wearable wireless device, away from the body or skin tissue. 2. The wearable wireless device according to claim 1, characterized in that it further includes a display located on the front side of the housing and a battery located on the back side of the housing. 3. The wearable wireless device according to claim 1, wherein the edge between the upper surface and the inclined surface, the edge between the inclined surface and the side surface, and the corners are rounded and without sharp edges. 4. The wearable wireless device according to claim 1, wherein the first and second antenna elements are embedded in the housing. 5. The wearable wireless device according to claim 1, wherein the first and second antenna elements are covered with a protective layer. 6. The wearable wireless device according to claim 1, wherein the first distance is less than the second distance. 7. The wearable wireless device according to claim 6, wherein the feed points of the first and second antenna elements to the circuit board are located near the first distance and far from the second distance. 8. The wearable wireless device according to claim 1, wherein the first antenna element is part of a first multi-frequency antenna, and the second antenna element is part of a second multi-frequency antenna. 9. The wearable wireless device according to claim 8, wherein the first multi-frequency antenna is a multi-frequency cellular antenna, and the second multi-frequency antenna is a GPS/WiFi/Bluetooth antenna. 10. The wearable wireless device according to claim 1, wherein the first antenna element is electrically connected to a first feed point, the second antenna element is electrically connected to a second feed point, and the first feed point and the second feed point are located on the same edge of the circuit board. 11. The wearable wireless device according to claim 1, wherein the first antenna element is shorter than the second antenna element. 12. The wearable wireless device according to claim 1, wherein the first and second antenna elements are bent around one or more corners of the housing. 13. The wearable wireless device according to claim 1, wherein the first and second antenna elements have a shared ground plane. 14. The wearable wireless device according to claim 13, wherein the first and second antenna elements having the shared ground plane constitute a dipole or a monopole. 15. The wearable wireless device according to claim 1, wherein the length of the first antenna element is 55mm to 90mm, the length of the second antenna element is 40mm to 65mm, and the relative permittivity of the material of the housing is 2.5 to 4.4. 16. The wearable wireless device according to claim 15, wherein the length of the first antenna element is 84 mm, the length of the second antenna element is 61 mm, and the relative permittivity of the housing is 2.5. 17. A wearable wireless device, characterized in that it comprises at least: The first antenna includes a first antenna element and a shared ground plane; The second antenna includes a second antenna element and the shared ground plane; and a housing accommodating the first and second antenna elements on a front and a back, wherein the front is positioned away from the user, and the back is positioned opposite the front and facing the user. Wherein, the first end of the first antenna vibrator and the first end of the second antenna vibrator are spaced apart by a first distance, and the second end of the first antenna vibrator and the second end of the second antenna vibrator are spaced apart by a second distance; the front side includes an upper surface, the back side includes a lower surface, the inclined surface connects the side to the upper surface, the first and second antenna vibrators are located on the inclined surface and are located around the display, along the end of the wearable wireless device, away from the body or skin tissue. 18. The wearable wireless device of claim 17, further comprising a display located on the front side of the housing, wherein the first and second antenna elements are bent around the display on the outer surface of the housing. 19. The wearable wireless device according to claim 17, wherein the first and second antenna elements are embedded in the housing or covered with a coating layer.